Unlocking Clean Energy's Potential: How Topological Surfaces Enhance Catalysts
The quest for sustainable energy solutions has led to the development of fuel cells and metal-air batteries, which are poised to play a pivotal role in a low-carbon future. However, a significant hurdle in this journey is the slow oxygen reduction reaction (ORR) that occurs on most materials, hindering efficiency and driving up costs. The challenge lies in finding catalysts that can accelerate this reaction, thereby reducing our energy footprint.
Two-dimensional (2D) topological materials have emerged as promising electrocatalysts, thanks to their unique electronic properties stemming from spin-orbit coupling (SOC). This phenomenon creates robust topological surface states (TSSs) that enhance charge transport. Yet, a critical oversight in previous studies was the assumption that these surfaces remain pristine and unchanged during reactions.
In reality, catalyst surfaces in electrochemical environments are far from ideal. They constantly interact with the surrounding electrolyte and reaction intermediates, forming electrochemical surface states (ESSs). To harness the potential of 2D topological materials, it is essential to understand how these realistic surfaces influence topological properties and catalytic performance.
To shed light on this, researchers at Tohoku University investigated monolayer platinum bismuthide (PtBi₂) as a model topological electrocatalyst. By combining quantum-level calculations with models that account for pH-dependent reactions, the team revealed the catalyst's true working surface under oxygen reduction conditions.
Their findings were eye-opening: PtBi₂ stabilizes at ORR-relevant potentials with a nearly monolayer of hydroxyl (HO) species covering its surface. This means the active surface is not the idealized topological surface but an HO-induced electrochemical surface state formed during operation.
The beauty of this surface reconstruction lies in its ability to preserve the material's topological nature. Instead of erasing it, it reshapes the electronic landscape, creating localized SOC-enabled surface states and a flat-band-like feature with a high density of electronic states near the Fermi level. These features enhance electronic coupling to ORR intermediates and reduce sensitivity to interfacial dipoles, much like roads guiding crowded traffic.
By explicitly considering pH effects, the researchers predicted that PtBi₂ achieves near-peak ORR activity in alkaline environments. This finding underscores the importance of evaluating catalytic performance under realistic electrochemical conditions rather than relying on idealized surface models.
Hao Li, a Distinguished Professor at Tohoku University's WPI-AIMR, emphasizes the significance of these findings: "Our research demonstrates that topological surface states can not only survive but also be optimized through electrochemical reconstruction. This discovery offers a practical design principle for next-generation electrocatalysts, where quantum topology and electrochemical surface chemistry must be considered in harmony."
The computational results have been made accessible to the scientific community through the Digital Catalysis Platform (DigCat), the world's first and largest experimental and computational catalysis database, developed by the Hao Li Lab. The platform provides a comprehensive resource for researchers to explore and advance catalysis technologies.
The research team's findings were published in the prestigious Journal of Physical Chemistry Letters on December 9, 2025, under the title "2D Topological Electrocatalysts with Spin−Orbit Coupling: Interplay between the “Electrochemical” and “Topological” Surface States."
Publication Details:
Title: 2D Topological Electrocatalysts with Spin−Orbit Coupling: Interplay between the “Electrochemical” and “Topological” Surface States
Authors: Heng Liu, Tran Ba Hung, Yuan Wang, Di Zhang, Yiming Lu, and Hao Li
Journal: The Journal of Physical Chemistry Letters
DOI: 10.1021/acs.jpclett.5c03589
For further insights and discussion, visit the publication's page on the Journal of Physical Chemistry Letters website.
